Novel magnetic composite photocatalyst ZnO/Bi24O31Br10@SrFe12O19with enhanced photocatalytic activity

This paper reports a novel magnetic composite photocatalyst ZnO/Bi24O31Br10@SrFe12O19 (ZBBSF) fabricated via a hydrothermal method. The structural characteristics of ZBBSF and the probable photocatalytic mechanism for rhodamine-B (RhB) degradation under visible light were investigated. Application of ZBBSF in a primary treatment of landfill leachate was also evaluated. Crystal and microscopic structure analyses verified that SrFe12O19 successfully compounded with the ZnO/Bi24O31Br10 composite (ZBB). The as-prepared ZBBSF composite displayed higher photocatalytic activity than ZBB for RhB degradation, and the decomposition level exceeded 95% after 30 min under visible light. Capturing experiments and electron spin resonance (ESR) analysis prove that •O2 – and •OH are the dominant activated radicals in RhB degradation. ZBBSF exhibited considerable stability after five cycles. Furthermore, ZBBSF exhibited a notable decolourisation effect on landfill leachate, reaching 56% in 250 min under visible light. These findings suggest that ZBBSF is a new composite photocatalyst with high efficiency and recyclability for organic wastewater disposal.